1. Field of the Invention
This invention relates to a new tensioner for an endless power transmission belt or the like and to a new method of making such a tensioner.
2. Prior Art Statement
It is known to provide a tensioner for a power transmission belt that is adapted to be operated in an endless path, the tensioner comprising a support member for being fixed relative to the belt, a belt engaging arm movably carried by the support member, and a spiraled spring having an outer end interconnected to the support member and having an inner end interconnected to the belt engaging arm for urging the belt engaging arm relative to the support member and against the belt with a force to tension the belt, the support member having a pivot opening passing therethrough, the belt engaging arm having a pivot part thereof rotatably disposed in the pivot opening so as to rotate therein, the support member having an internal wall provided with a slot passing completely therethrough and through which the outer end of the spring extends to interconnect the outer end of the spring to the support member. For example, see the U.S. patent to Henderson, U.S. Pat. No. 4,952,197 and the U.S. patent to Henderson, U.S. Pat. No. 4,596,538.
It is also known to applicant to form the support member from polymeric material and have an annular surface disposed substantially concentrically about the longitudinal axis of the pivot opening thereof so that an annular surface of the belt engaging arm can be disposed directly in sliding engagement with the annular surface of the support member without requiring an anti-friction bushing means to be disposed therebetween. For example, see the copending patent application of Dewey D. Henderson Ser. No. 08/326,559, filed 20 Oct. 1994, (Dayco Products, Inc. Docket No. 93-11).
It is also known to have the spiraled spring for a tensioner be offset between the inner end thereof and the outer end thereof and be so arranged in the tensioner that the spiraled spring urges the cooperating annular surfaces of the support member and the belt engaging arm toward each other with a certain force. For example, see the copending patent application of Mark P. Foley, Ser. No. 124,749, filed Sep. 21, 1993.
It is also known to have the cooperating surfaces of the support member and the belt engaging arm respectively angled to the longitudinal axis of the pivot opening of the support member. For example, see the U.S. patent to Sidwell et al, U.S. Pat. No. 5,149,306.